The invention relates to a method for chemically treating substrates in which at least one substrate is subsequently subjected to a chemical treatment, a washing step, and a drying step, and a device for performing the aforementioned chemical treatment.
To date an automatic wet treatment device has a series of tubs or of reservoirs for a sequence of chemical wet processes. After completion of a certain chemical process sequence the substrate, for example, a silicon wafer, is immersed in a separate washing, respectively, rinsing tub and subsequently dried.
The drying of the substrate can, for example, be performed with a centrifuge, but can also be carried out during the slow removal of the substrate from the washing tub.
From European document 0 385 536 the so-called Marangoni dryer is known. In the method disclosed in this patent a vapor is applied to the substrate in addition to the slow removal of the substrate from the bath, whereby the vapor does not condense on the substrate, but diffuses into the liquid. At the liquid meniscus of the substrate surface a concentration gradient will result and thus a surface tension gradient. This gradient results in a liquid movement away from the substrate into the liquid (Marangoni effect) and leads to a residue-free drying of the substrate.
From U.S. Pat. No. 4,722,752 a device and a method are known for rinsing and drying wafers, whereby the wafer is enclosed in a cassette. The wafers are removed from the rinsing bath separate from the cassette and are subsequently inserted into the cassettes that have been slowly removed and dried also.
The described device, respectively, methods have the following disadvantages: The rinsing reservoir in each case is a separate bath from the other process reservoirs and serves only for rinsing the substrate. However, an individual and separate rinsing reservoir means an increased space requirement. Furthermore, the substrate must be moved through the surface of the fluid used for the chemical treatment into the air and subsequently must be inserted into the rinsing fluid which, and this may have disadvantageous effects with respect to the particle contamination of the substrate, as is well known in the art. This is especially true for hydrophobic surfaces, for example, after HF treatment. Furthermore, the insertion into, respectively, removal of the substrates from the various baths for chemical treatment, respectively, the rinsing step results in an increased time expenditure. Also, the known devices, respectively, methods always require a cassette (carrier) for handling the substrates.
It is therefore an object of the invention to provide a method for chemically wet treating, respectively, a device for such a method which economizes the process sequence of an automatic wet treatment device, i.e., saves time and space. A further object of the invention is to minimize the contamination of the substrate during such a sequence of chemical wet processes. Finally, a further object of the invention is to make obsolete the need for a cassette or similar holding device for the substrate in connection with the insertion of the substrate into respectively, the removal of the substrate from the reservoirs.